moore



I. LADOFF AND R. W. E. MOORE.

ARC LAMP ELECTRODE.

APPLICATION FILED JUNE 29. 1914.

1 ,3 1 7, 1 99 Patented Sept. 30, 1919.

ATTORNEY invented a idly consumed in the arc,

' ficiency of luminous arcs may UNITED STATES PATENT OFFICE.

IBADOB LADOFF AND RALPH W. E. M00315, 0]! 'WILKINBBURG, PENNSYLVANIA, ASSIGNOBS T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A. CORPORATION OF PENNSYLVANIA.

ABC-LAMP ELECTRODE.

Specification of Letters Patent.

Patented Sept. 30, 1919.

Application area June 29, 1914. Serial No. 847,784.

To all whom it may concern: I

Be it known that we, ISADOR Lanorr, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania and RALPH W. E. MOORE, a citizen of the United States, and a resident of W'ilkinsburg, in the county of Allegheny and'State of Pennsylvania, have new and useful Improvement in Arc-Lamp Electrodes, of which the followin is a specification.

%)ur invention relates to are lamps, and it has special reference to lamps of the flaming or luminous ty e.

More particu arly, our invention relates to electrodes which are adapted to be used in lamps of the above-mentioned type and which are of such a character as to conserve the heat of the arc in order that it may be utilized in increasing the luminous eliiciency of the are.

In an arc lamp employing ordinary carbon electrodes, the arcing end or incandescent crater of the positive electrode supplies the major portion of the light flux emitted from the arc. Inasmuch as a great amount of heat is required to obtain and maintain this incandescent crater, the electrode is rapthus necessitating its replacement at frequent intervals of time. To obviate the necessity of replacing the consumable positive electrode at each trim, slowly consumable positive electrodes have been employed in combination with more rapidly consumable negative electrodes containing light-giving materials. This type of arc lamp is known as the metallic flame arc lamp, and the light emitted from the are results principally from the luminescense of the light-giving particles pro ected into the are on the combustion of the consumable negative electrode.

The most satisfactory slow-consumable electrodes are made of metallic copper, a material of good electrical conductivity and high heat conductivity. Moreover, copper electrodes are particularly desirable because they are not readily oxidized in the are. As disclosed in patent application of Isador Ladofi', Serial No. 847,815, filed June 29, 1914, and assigned .to {the Westinghouse Electric & Manufacturing Company, the efbe greatly increased if the heat developed in the arc is, as

far as practicable, fprecluded from being conducted away by the electrodes. Copper anodes found most suitable are made with substantially large cross sectional areas, and therefore, their radiating surfaces are 0 such large extent that large quantities of heat are conducted away from the arc. It has been proposed to make the anodes of materials having good electrical conductivity but low heat conductivity, but such mater als rapidly consume in the are, thus necessltating frequent replacement of the anode. The materials of this character that have been found m0st suitable are graphite, cold rolled steel and ilmenite.

We propose to provide an anode for use in flaming arc lamps which is of good electrical conductivity, low heat conductivity, and not readily consumed in the are.

For a better understanding of our invention, reference may be had to the following description and the accon'ipanying drawing in which Figure 1 is a view, partially in elevation and partially in section, of the ends of a pair of cooperating arc lamp electrodes embodying our invention, and Figs. 2, 3 and 4. show modified forms of our electrode.

Referrin to Fig. 1, a lower electrode 1 made of ight-giving materials yielding luminous vapors, constitutes the cathode of our arc lamp. An upper electrode or anode 2 is provided with a copper tip 3 which is secured to a main electrode portion 4. The portion 4 of the electrode is preferably made of graphite or cold rolled steel, or other material which is of good electrical conductivity but of low heat conductivity. The tip 3 is provided with a threaded shank 5 which firmly secures the tip to the portion 4, thereby lowering the contact resistance between the tip 3 and the main portion 4. As before mentioned, the copper tip is but slowly consumable in the arc, and the main portion 4 is of such character as to preclude the rapid conduction of the heat away from the are. In place of the copper tip 3, a tip of silver or any other metal of similar nature which accomplishes the same purpose may be employed. It is important, however, that the thickness of the copper anode ti shall be so proportioned that the amount of heat lost by convection does not overbalance the amount of heat saved by substantially precluding the conduction of the heat away from the arc. Copper tips from .25 inch to .125 inch have been found to be the most economical for are lamps-adapted to be operated on commercial circuits.

Fig. 2 shows, in cross section, a modified form of our anode. In this instance, a copper tip 6 is provided with a long shank 7 which is centrally disposed in the main portion 4 of the electrode. By this construction, the electrical conductivity of the electrode 2 is greatly increased.

In Fig. 3, the copper shank 7 of the tip 6 is engaged by a screw 8 threaded through a metallic ring 9 which embraces the mam portion 4.- of the electrode. The ring 9 may be provided with a clip (not shown) by means of which the electrical circuit may be completed without the necessity of the current passing through the remainder of the main portion 4: of the electrode.

In Fig. 4, the copper tip 10 is electrically connected by a conductor 11 to the ring 9, thereby obviating the necessity of the cur rent of the are passing through the main portion 4 of the electrode.

While we have shown and described several embodiments of our invention, it will be understood that many modifications may be made without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. A positive electrode for are lamps comprising a main portion consisting wholly of a material of relatively low heat conductivity and relatively high electrical conductivity, and an arcing end consisting of a disk of conducting material free from ready oxidation in the are.

2. A positive electrode for are lamps comprising a main portion consisting wholly of a material of relatively low heat conductivity and relatively high electrical conductivity and an arcing end composed wholly of a relatively slowly consumable conducting material of relatively high heat conductivity.

3. A positive electrode for are lamps comprising a main portion consisting wholly of a material of relatively low heat conductivarmee ity and relatively high electrical conductivity, and-an arcin end composed Wholly of conducting material free from readyoxidation in the arc.

A positive electrode for are lamps comprising a main ortion consisting wholly of a material of re atively low heat conductiva copper disk.

7 A positive electrode for are lamps comprising a main portion consisting wholly of graphite, and an arcing end consisting Wholly of metallic copper.

8. An arcing electrode comprising a body portion of relatively low heat conductivity and of substantially uniform cross-sectional area and an arcing end composed of copper and having substantially the same crosssectional area as the said body portion.

9. An arcing electrode comprising a body portion of relatively low heat conductivity and of substantially uniform cross-sectional area, and an arcing end composed of copper and attached to the said body portion by means of a central screw-fastener extending from the said disk into the end of the said body portion.

In testimony whereof, we have hereunto sgpicribed our names this 25th day of June, 1

ISADOR LADOFF. RALPH W. E. MOORE.

Witnesses:

GoLDIE E. MCGEE, B. B. HINEs. 

